The skill of preparing an abstract lies in the ability of the worker-up to arrange
the items abstracted from the dimension sheets in bill order. This may not seem
too difficult a task to anyone who has not tried it, but when tender documents are
being prepared in a rush against a tight deadline (which must be 99% of the
time!) the worker-up may be handed the dimension sheets in small lots but must
lay out his abstract to accommodate items he has not yet seen.

Building Quantities Explained (Building & Surveying)
Seeley and Winfield's Building Quantities Explained: Irish Edition (Building and Surveying Series)